Method for producing hydrogen and apparatus for supplying hydrogen

ABSTRACT

A method for producing hydrogen by contacting water, steam or gas containing steam with iron or iron oxide, wherein the iron or iron oxide is added with at least one metal of Rh, Ir, Ru, Pd, Pt and Os and at least one metal of Ti, Zr, V, Nb, Cr, Mo, Al, Ga, Mg, Sc, Ni and Cu. The method provides a medium for producing hydrogen which is capable of producing hydrogen at relatively low temperature and at a great generation rate, is free from the decrease of activity, and is resistance to repeated oxidation and reduction, which leads to the decomposition of water and production of hydrogen with good efficiency.

TECHNIICAL FIELD

The present invention relates to technology for efficiently producinghydrogen by decomposing water.

TECHNIICAL FIELD

Partial oxidation or steam reforming method using petroleum or naturalgas as raw material emits a huge quantity of carbon dioxide uponhydrogen synthesis. UT-3 cycle and a method disclosed in Japanese PatentApplication Laid-open No. Hei 07-267601 using solar thermal power havebeen proposed as methods wherein no carbon dioxide is emitted. However,these methods require a large system upon using solar thermal power, andaccordingly, require a large cost.

In place of high pressure gas cylinder, use of hydrogen absorbing alloyhave been variously proposed as means for safely storing andtransporting hydrogen. However, there is a problem that hydrogenabsorption in hydrogen absorbing alloy requires high hydrogen pressure,that under the condition wherein hydrogen is absorbed in hydrogenabsorbing alloy, it cannot be used in the air and steam atmosphere, andthat it require a large cost.

Further, in case of fuel cells wherein hydrogen and air are used as rawmaterials, method for supplying hydrogen by way of steam reforming ofmethanol or gasoline is generally used and many inventions have beenproposed. However, in either proposed methods, generation of carbonmonoxide and that of carbon dioxide take place simultaneously, andespecially, carbon monoxide requires a device for decreasing itsconcentration to a value lower than 10 ppm so as to avoid poisoning ofelectrodes of fuel cells, and accordingly, the cost is extremely high.

Steam iron method is known as a method for producing hydrogen fromwater. In this method, oxidation and reduction of only iron, i.e.,Fe→FeO(Fe₃O₄.)→Fe, is used in the reaction. The reaction requires a hightemperature, for example higher than 600° C., and so-called sinteringwherein metal iron gathers occurs after repetition of oxidation andreduction, and there is a problem that activities of metal irondecreases in a short time. Accordingly, medium for producing hydrogen,i.e., oxidation and reduction material, which is free from sinteringphenomenon, which has durability and which shows high activities, isrequested.

Taking the above-described conventional problems into consideration, inthe previously filed Japanese Patent Application No. 2001-102845, theinventor of the present application proposed a method for producinghydrogen wherein specified medium for producing hydrogen, i.e.,oxidation and reduction material, is used, by which medium hydrogenproducing reacting rate is high, activities of which medium are notdecreased, and which medium is durable against repetition of oxidationand reduction. More specifically, a method for producing hydrogeninvolves contacting water, steam or gas containing steam with iron oriron oxide, wherein the iron or iron oxide is added with at least onemetal of Ti, Zr, V, Nb, Cr, Mo, Al, Ga, Mg, Sc, Ni and Cu wherebyhydrogen is produced efficiently.

An object of the present invention is to provide a method whereinhydrogen is produced by decomposing water more efficiently than aconventional method for producing hydrogen from water, or whereinhydrogen can be produced at a temperature lower than that used in aconventional method, and the present invention provides a method forproducing hydrogen taking the invention proposed in the above-describedJapanese Patent Application No. 2001-102845 into consideration.

DISCLOSURE OF THE INVENTION

According to the present invention, as defined in claim 1, theabove-described object is achieved by method for producing hydrogen bycontacting water, steam or gas containing steam with iron or iron oxide,wherein the iron or iron oxide is added with at least one metal of Rh,Ir, Ru, Pd, Pt and Os.

Further, as defined in claim 2, the above-described object is achievedby method for producing hydrogen by contacting water, steam or gascontaining steam with iron or iron oxide, wherein the iron or iron oxideis added with at least one metal of Rh, Ir, Ru, Pd, Pt and Os and atleast one metal of Ti, Zr, V, Nb, Cr, Mo, Al, Ga, Mg, Sc, Ni and Cu.

In the present invention, water used as a raw material may be notnecessarily pure water and may be such water as from water-supply orindustrial water.

Iron used as a raw material in the present invention may be malleableiron, or a iron compound such as iron oxide, iron nitrate, iron chlorideor iron sulfate.

Further, the first metal added to iron or iron oxide in the presentinvention is at least one of the platinum group, and it is preferredthat at least one of Rh, Ir, Ru, Pd, Pt and Os is selected.

In addition, in the present invention, the metal added to iron or ironoxide is at least one of the platinum group, and as the second metal, atleast one metal of Ti, Zr, V, Nb, Cr, Mo, Al, Ga, Mg, Sc, Ni and Cu maybe added.

It is preferred that the amount of the metal of the platinum group addedto iron or iron oxide, measured in molarity of the metallic atom, isprepared between 0.1 and 30 mol % of all the metallic atoms, and morepreferably, between 0.5 and 15 mol %.

Either the first added metal, i.e., metal of the platinum group, or thesecond added metal does not achieve increase of hydrogen producingefficiency when the added amount is less than 0.1 mol %, and decreasesoxidation and reduction efficiency when the added amount is more than 30mol %.

The method for adding metal may be physical mixing or impregnatingmethod, and preferably, coprecipitation method. In order to efficientlyuse the prepared iron compound, it is formed in a shape having largesurface suitable for reaction, such as a pellet, cylinder, honey-combshape, or non-woven fabric, and is used in decomposing reaction ofwater.

The iron compound is placed in a reaction vessel and is reduced forexample by hydrogen. Water, steam or gas containing steam is made incontact with the reduced iron compound, and hydrogen is produced. Inthis occasion, iron reacted with water becomes iron oxide. The oxidationand reduction reaction may be carried out at a temperature lower than600° C.

According to the present invention, hydrogen can be supplied at low costto fuel cells for local installation, for factory use, or for domesticuse without generating carbon monoxide which poisons electrodes of fuelcells. The produced hydrogen is not only used in fuel cells but alsowidely used in hydrogen supply means such as hydrogen burner. Further,the reduced iron compound is filled with a vessel as a portable hydrogensupply cassette, which may be used as hydrogen supply means for theabove-described fuel cells and so on.

Further, the present invention provides apparatus for supplying hydrogencharacterized in

-   -   that it comprises a portable cassette accommodating a hydrogen        producing medium therein and providing with at least two means        for mounting pipings:    -   the hydrogen producing medium comprises iron or iron oxide as        main element and metal of the platinum group, or metal of the        platinum group and metal of the above-described second metal,        added thereto;    -   the cassette is capable of being added with water or steam        through one of the piping mounting means, and is capable of        supplying hydrogen generated by decomposing water to hydrogen        consuming device through the other piping mounting means.

Heater may be disposed within the cassette. Further, the cassette may beprovided with pipings for supplying inert gas or air. The air issupplied when heat of the reaction generated by reaction between air andreduced metal oxide is used upon water decomposing reaction.

Iron oxidized by reaction with water is reduced again by hydrogen andcan be repeatedly used as oxidation and reduction medium withoutdecreasing its activities.

It is guessed that the reasons for achieving the above-describedadvantages reside in prevention of sintering, promotion of diffusionrate of oxygen in solid body, increase of water decomposing activitiesat surface, and so on.

Especially, when metal of platinum group is added as in the presentinvention, there is a tendency that reaction rate of reduction andreaction rate of oxidation increase remarkably.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be explained in detail with reference tothe attached drawings which illustrate some embodiments of the presentinvention, wherein:

FIG. 1 is a schematic view showing the reaction system of iron compoundwhich has been used in the embodiment of the present invention;

FIG. 2 is a diagram showing the relationship between hydrogen producingrate and reaction temperature upon decomposing water;

FIG. 3 is a diagram showing the total amount of produced hydrogen;

FIG. 4 is a view showing the construction of the present inventionwherein the reaction vessel accommodating hydrogen producing medium anddevice for supplying water are connected by means of pipings; and

FIG. 5 is a view showing the condition wherein a cassette accommodatinghydrogen producing medium which has been reduced is connected to fuelcells.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1

A schematic view showing the reaction system of iron compound which hasbeen used in the present embodiment is illustrated in FIG. 1. The deviceillustrated in FIG. 1 is a reaction device of non-pressure fixed bedcirculation type, and a part of reaction gas was collected and wasmeasured by means of gaschromatograph.

Iron compound accommodated in the reaction vessel was prepared inaccordance with the following coprecipitation method, i.e., urea method.More specifically, in 5 liter of water, which had been deaired for 5minutes by means of ultra sonic, 0.194 mol of iron nitrate (III)9-hydrate (Fe(NO₃)₃.9H₂O: manufactured by Wako Pure Chemical Industries,Ltd.), 0.006 mol of rhodium chloride (RhCl₃.3H₂O: manufactured by WakoPure Chemical Industries, Ltd.) as chloride of metal of the platinumgroup to be added, and 10 mol of urea (NH₂(CO)NH₂: manufactured by WakoPure Chemical Industries, Ltd.) as precipitant were added and weresolved. While the mixed solution was stirred, it was heated at atemperature of 90° C. and was maintained at the same temperature for 3hours. After completion of reaction, it was left for 16 hours and wasprecipitated, and then it was filtered by suction. The preciptation wasdried for 24 hours at 80° C. Thereafter, it was burned in air for 5hours at 100° C., 5 hours at 300° C., and 10 hours at 500° C. The atomsof the platinum group to be added in the sample was set to be 3 mol ofall the metallic atoms in the sample. The sample was pulverized intogranule condition in a mortar after it was burned, and it was used inthe experiments.

First the sample was put into the reaction vessel, and after air in thesystem was purged by argon, i.e., inert gas, hydrogen was introduced,and it was heated from 290° C. to 550° C. at an increasing rate of 7.5°C. per minute and was reduced while it was maintained at 550° C. untilconsumption of hydrogen disappeared.

After completion of reducing reaction by means of hydrogen, argon wasintroduced into the device so that hydrogen remaining within the vesselwas exhausted. Thereafter, water was vaporized at a rate of3.6×10⁻mL/min, i.e., 200 μmol/min, by means of a carburetor, andvaporized water and argon gas which was used as a carrier gas wasintroduced into the reaction vessel so as to effect decomposing reactionof water. In this case, the reaction vessel was heated from 120° C. to600° C. at an increasing rate of 4° C. per minute.

FIG. 2 is a diagram showing the results of the water decomposingreaction, i.e., relationship between reaction temperature and hydrogenproducing rate, obtained through the above-described reaction whereinthe sample prepared by the above-described coprecipitation method, i.e.,urea method, was used after it was so measured that the Fe content was0.2 g. With respect to Ir, Ru, Pd and Pt belonging to the platinum groupin addition to Rh, samples were similarly prepared in thecoprecipitation method, and water decomposing reactions were measuredsimilarly to the above-described Rh.

As it is shown in FIG. 2, iron oxide with no addition (X symbol)scarcely generates hydrogen at a temperature lower than 300° C., and itshydrogen producing rate shows maximum at a temperature of 500° C.Contrary to this, with respect to iron oxide with Rh added thereto (◯symbol), a sufficient generation of hydrogen can be confirmed even at alow temperature below 300° C., and its hydrogen producing rate shows apeak at a temperature of about 350° C. With respect to iron oxide withIr added thereto (● symbol), like the iron oxide with Rh added thereto,a sufficient generation of hydrogen can be confirmed even at a lowtemperature below 300° C., and its hydrogen producing rate shows a peakat a temperature between of about 350 and 400° C. Iron oxide with Ruadded thereto (Δ symbol) has a peak of hydrogen producing rate at about400° C., and its hydrogen producing rate exceeds the maximum of the ironoxide with no addition even at a temperature lower than 400° C. Ironoxide with Pd added thereto (▴ symbol) has a peak of hydrogen producingrate at about 500° C. and its hydrogen producing rate already exceedsthe maximum of the iron oxide with no addition at a temperature of about400° C. Iron oxide with Pt added thereto (□ symbol) has a peak ofhydrogen producing rate at a temperature lower than 500° C., and itshydrogen producing rate already exceeds the maximum of the iron oxidewith no addition at a temperature of about 450° C.

As described above, in the diagram shown in FIG. 2, any iron oxides withmetal of the platinum group added thereto show their peaks of hydrogenproducing rate at a temperature lower than that of the peak for the ironoxide with no addition and the numerical value of their peaks are higherthan that of the peak for the iron oxide with no addition. From theresults, it is confirmed that hydrogen can be generated at a lowtemperature, in other words, there is an advantage that hydrogenproducing rate by decomposing water at a low temperature is enhanced,when metal belonging to the platinum group is added to iron oxide.

Embodiment 2

In Embodiment 2, like in Embodiment 1, the reaction device ofnon-pressure fixed bed circulation type illustrated in FIG. 1 was used,and a part of reaction gas was collected and was measured by means ofgaschromatograph.

Iron compound accommodated in the reaction vessel was prepared inaccordance with the following coprecipitation method, i.e., urea method.More specifically, in 5 liter of water, which had been deaired for 5minutes by means of ultra sonic, 0.188 mol of iron nitrate (III)9-hydrate (Fe(NO₃)₃.9H₂O: manufactured by Wako Pure Chemical Industries,Ltd.), 0.006 mol of rhodium chloride (RhCl₃.3H₂O: manufactured by WakoPure Chemical Industries, Ltd.) as chloride of metal of the platinumgroup to be added, 0.006 mol of aluminum nitrate (Al(NO₃)₃.9H₂O:manufactured by Wako Pure Chemical Industries, Ltd.) as chloride of thesecond metal to be added, and 10 mol of urea (NH₂(CO)NH₂: manufacturedby Wako Pure Chemical Industries, Ltd.) as precipitant were added andwere solved. While the mixed solution was stirred, it was heated at atemperature of 90° C. and was maintained at the same temperature for 3hours. After completion of reaction, it was left for 16 hours and wasprecipitated, and then it was filtered by suction. The preciptation wasdried for 24 hours at 80° C. Thereafter, it was burned in air for 5hours at 100° C., 5 hours at 300° C., and 10 hours at 500° C. Each ofthe atoms of the platinum group to be added and the atoms of the secondmetal to be added in the sample was set to be 3 mol of all the metallicatoms in the sample. The sample was pulverized in a mortar after it wasburned, and it was shaped in a pellet.

First the sample was put into the reaction vessel, and after air in thesystem was purged by argon, i.e., inert gas, hydrogen was introduced,and the sample was heated at 470° C. for one hour and was reduced.

After completion of reducing reaction by means of hydrogen, nitrogen wasintroduced into the device so that hydrogen remaining within the vesselwas exhausted. Thereafter, the reaction vessel was heated at atemperature of 300° C., and water was vaporized at a rate of 0.1 mL/min,i.e., 5,556 μmol/min, by means of a carburetor, and vaporized water andnitrogen gas which was used as a carrier gas were introduced into thereaction vessel so as to effect decomposing reaction of water.

After completion of the above-described water decomposing reaction,reducing reaction was again took place, and thus, the water decomposingreaction was repeated for three times.

FIG. 3 is a diagram showing the comparison of the total amounts ofhydrogen produced by the above-described methods wherein the sampleswhich had been prepared in accordance with the coprecipitation method,i.e., urea method, were measured so that the total Fe content became 4.0g. With respect to the combination of Pt, Ru, Pd and Ir belonging to theplatinum group and Al, the combination of Rh and Mo, and addition of Aland Mo, in addition to the combination of Rh and Al, samples weresimilarly prepared in the coprecipitation method, and their totalamounts of the produced hydrogen were measured similarly to theabove-described Rh.

As it is shown in FIG. 3, iron oxide having Rh solely added theretogenerates well more hydrogen compared to iron oxide with no addition,and its amounts of hydrogen generated at the first stage and the secondstage are bigger than that by iron oxides having Al or Mo solely addedthereto, and even at the third stage, its amount of generated hydrogenis almost the same order.

Further, iron oxide having Al added thereto as the second metal inaddition to Rh, i.e., Rh—Al added iron oxide, generates well morehydrogen compared to iron oxide with no addition, and its amounts ofgenerated hydrogen are bigger than that by iron oxides having Al or Mosolely added thereto, and degradation by repetition is not observed. Inaddition, as is shown in FIG. 3, with respect to Pt—Al added iron oxide,Ru—Al added iron oxide, Pd—Al added iron oxide, Rh—Mo added ironoxide,and Rh—Al added iron oxide show similar tendencies.

From the results, it is confirmed that the platinum group (Rh, Ir, Ru,Pd, Pt and Os) which is the first metal contributes to increase thehydrogen producing efficiency, and at the same time, achieves theadvantage to proceed the reducing reaction. In this embodiment, whenreduction takes place while the reducing conditions are kept constant,amount of reduced iron oxide can be guessed from the amount of thegenerated hydrogen, i.e., the oxidized amount, and the difference in thereducing rates can be guessed thereby.

Al or Mo which is the second metal to be added contributes not only toincrease the hydrogen producing efficiency, but also to achieve effectfor avoiding the degradation by repetition. Al or Mo is preferable forthe second added metal, and Ti, Zr, V, Nb, Cr, Ga, Mg, Sc, Ni, or Cu mayalso be used.

Therefore, when metal added to iron may be only the first one belongingto the platinum group, the first metal contributes to increase thehydrogen producing efficiency, and hydrogen can be stably generated.Further, by addition of the second metal, activity for water decomposingreaction can be maintained for repeated times, even if the waterdecomposing and reducing reactions are repeated.

MODE FOR INDUSTRIALLY CARRYING OUT THE INVENTION

The mode for industrially carrying our the present invention isillustrated in FIG. 4. FIG. 4 is a schematic view of one embodiment of asystem, wherein a reaction vessel 1 accommodating hydrogen producingmedium 9 of the present invention and a device 2 for supplying water areconnected by means of pipings, so that they are constructed as acassette 10 for supplying hydrogen.

The hydrogen producing medium 9 is metal added iron oxide of the presentinvention, and it comprises iron or iron oxide as main element and atleast one metal of Rh, Ir, Ru, Pd, Pt and Os added thereto, or itcomprises iron or iron oxide as main element, at least one metal of Rh,Ir, Ru, Pd, Pt and Os added thereto and at least one metal of Ti, Zr, V,Nb, Cr, Mo, Al, Ga, Mg, Sc, Ni and Cu added thereto.

The reaction vessel 1 for performing water decomposing and reducingreactions is connected to the device 2 for supplying water by means of apiping 3, and the device 2 for supplying water is connected to a piping4 for introducing inert gas or air. The inert gas may be for example,nitrogen, argon or helium. Nitrogen (inert gas) is used as carrier gasfor performing the reaction smoothly or for purging air (oxygen) in thesystem, but it is not always necessary. Air is used when the heatgenerated upon reaction between air and reduced iron oxide is used tothe water decomposing reaction upon water decomposing reaction, but itis not always necessary. In place of air, oxygen or inert gas containingoxygen may be used. Piping 5 may be connected to the cassette 10 so thatthe water supply device in the cassette 10 can be supplemented withwater from the outside of the cassette 10.

The reaction vessel 1 is connected to piping 6 for exhausting hydrogenor steam, and it feeds hydrogen generated by water decomposing reactionto a system which needs hydrogen, such as polymer electrolyte fuelcells. A heater 7 is disposed within the cassette 10 as a heat sourcefor supplying heat for water decomposing reaction and reducing reaction.The heat source may be any of an electric furnace, a heater, inductionheating, catalytic combustion heating, heating by chemical reaction. Thereaction vessel 1 is made of metal such as stainless steel or aluminum,ceramics such as alumina or zirconia, or heat resisting plastics such asphenol or poly phenylene sulfide, and has a construction resistant toheat and inside and outside pressure.

The cassette 10 has heat insulator 7 a such as silica fiber insertedthereinto and is covered by cover 11. Filters 8 are disposed at the gasinlet and outlet of the cassette 10.

Further, although the cassette 10 has water supplying device disposedtherein in the embodiment illustrated in FIG. 4, water may be directlysupplied into the reaction vessel 1 from the water supply piping 5without disposing such a device. When nitrogen is not used for waterdecomposing reaction, the water supply piping 5 may be omitted, andwater may be supplied from the piping 4. Further, although the heater 7is disposed in the cassette 10 in this embodiment, the heater may not bedisposed in the cassette and may be disposed separately.

FIG. 5 is a view showing the condition wherein a cassette 10accommodating hydrogen producing medium which has been reduced isconnected to fuel cells 20. The reduced hydrogen producing medium reactswith water and produces hydrogen from the cassette 10. The producedhydrogen is supplied to anode 21 of polymer electrolyte fuel cellthrough piping 15 which is connected to the polymer electrolyte fuelcell. Air is introduced to the cathode 22 of polymer electrolyte fuelcell, and electric power is taken out through the reaction betweenhydrogen and oxygen in the air.

INDUSTRIAL APPLICABILITY

According to the present invention, in a method for producing hydrogenwherein water, steam or gas containing steam is contacted with iron oriron oxide, since metal of the platinum group is added to the iron oriron oxide, hydrogen can be produced at a low temperature, and hydrogenproducing rate is high. In addition, the total hydrogen producing amountat a certain temperature can be large.

Further, according to the present invention, since metal of the platinumgroup and the above-described second metal are added to the iron or ironoxide, the total hydrogen producing amount can be large, and the totalhydrogen producing amount remain at high level even after waterdecomposing reaction and reducing reaction are repeated, since theiractivities are not degraded. Accordingly, the oxidizing and reducingmedium, which has already produce hydrogen, can be recycled if it isreduced again after it produces hydrogen.

According to the present invention, since the hydrogen producingreaction rate and the total hydrogen producing amount per unit weightare increased, hydrogen can be remarkably efficiently supplied wit thesystems such as polymer electrolyte fuel cells which need hydrogen.

Although the metals which are added in the present invention areexpensive except for iron, hydrogen can be produced at low cost, sincesmall amount of such metals, i.e., between 0.1 and 30 mol %, issufficient for increasing the reaction efficiency.

Further, the gas generated from the cassette is pure hydrogen and steamand no impurities are contained, and accordingly, electrodes of fuelcells of low temperature use type, such as polymer electrolyte fuelcells, phosphoric acid type fuel cells, or KOH type fuel cells, are notpoisoned, and no device for decreasing CO is necessary, and therefore,since the system can be a simple construction, and economical advantagesare very large.

1. A method for producing hydrogen by contacting water, steam or gascontaining steam with iron or iron oxide, wherein the iron or iron oxideis added with at least one first metal of Rh, Ir, Ru, Pd, Pt and Os andat least one second metal of Ti, Zr, V, Nb, Cr, Mo, Al, Ga, Mg, Sc, Niand Cu, and the amount of the added first metal and the amount of theadded second metal added to iron or iron oxide, measured in molarity ofthe metallic atom, are between 0.1 and 30 mol % of all the metallicatoms, respectively.
 2. A method for producing hydrogen by contactingwater, steam or gas containing steam with iron or iron oxide, whereinthe iron or iron oxide is added with at least one metal of Rh, Ir, Ru,Pd, Pt and Os and at least one metal of Ti, Zr, Nb, Cr, Al, Ga, Mg, Scand Cu.
 3. A method for producing hydrogen according to claim 1, whereinthe addition of metal is done by means of coprecipitation method. 4.Apparatus for supplying hydrogen characterized in that it comprises aportable cassette accommodating a hydrogen producing medium therein andproviding with at least two means for mounting pipings: the hydrogenproducing medium comprises iron or iron oxide as main element and atleast one first metal of Rh, Ir, Ru, Pd, Pt and Os added thereto and atleast one second metal of Ti, Zr, V, Nb, Cr, Mo, Al, Ga, Mg, Sc, Ni andCu added thereto; the amount of the added first metal and the amount ofthe added second metal added to iron or iron oxide, measured in molarityof the metallic atom, are between 0.1 and 30 mol % of all the metallicatoms, respectively; and the cassette is capable of being added withwater or steam through one of the piping mounting means, and is capableof supplying hydrogen generated by decomposing water to hydrogenconsuming device through the other piping mounting means.
 5. Apparatusfor supplying hydrogen characterized in that it comprises a portablecassette accommodating a hydrogen producing medium therein and providingwith at least two means for mounting pipings: the hydrogen producingmedium comprises iron or iron oxide as main element and at least onemetal of Rh, Ir, Ru, Pd, Pt and as and at least one metal of Ti, Zr, Nb,Cr, Al, Ga, Mg, Sc and Cu added thereto; the cassette is capable ofbeing added with water or steam through one of the piping mountingmeans, and is capable of supplying hydrogen generated by decomposingwater to hydrogen consuming device through the other piping mountingmeans.